Telephone system.



F. R. PARKER.

TELEPHONE SYSTEM.

APPLICATION FILED JUNE 20, 1904.

Patented Mar. 17, 1914.

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FREDERICK R. PARKER, OF CHICAGO, ILLINOIS.

TELEPHONE SYSTEM.

ncaaser.

Specification of Letters Patent.

Patented Mar. f7, 1914..

Application filed time 20, 1904. Serial no. 213,284.

To all whom, it may concern Be it known that I, Fnnonnron R. PARKER, acitizen of the United States of America, residing at Chicago, in thecounty of Cook and State of Illinois, have invented a new orannunciator; to provide improved means for disconnecting the subscribersindicator or annunc1ator and the central statlon signahng apparatus andsource of electrical supply from the line when the latter is in useeither for conversation or during the operation of calling asubscriberjto provide improved means for operating and con trolling thesubscribers disconnect or supervisory indicator or annunciator; toprovide an improved arrangement of the line relays in the system; toprovide an improved arrangement of the supervisory relays in the system;and to provide improved means for allowing the subscribers to carry onsecret conversation by preventing the operator from listeningin on thelines during such conversation.

Other objects will be apparent from the following specification.

In my present invention I have shown a talking telephoneline extendingdirect from the subscribers station, or stations, to the connectionterminals or spring acks of the central station switchboard, andincluding the windings, or winding, of a linecut-ofi relay therein. ThenI have shown a signaling circuit extending from the talking telephoneline, between the line cut-off relay and the subscribers station, tosignaling apparatus and a central source of electric current. Then thecut-ofi relay is energized, it disconnects the said signaling circuitfrom the talking telephone line. The cut-off relay is adapted to beoperated by any form of electric current, such as a direct, alternating,intermittent, interrupted, or pulsating current. V

It has been the usual practice heretofore, to provide a relay includedin a local circuit,

for cutting the central source of current and signaling apparatus fromthe talking telephone line, but it is an object of the present inventionto utilize the talking circuit itself for actuating the cut-off relay.

In the subscribers telephone instrument I employ any suitable circuitarrangement for opening and closing the line circuit or for varying thecurrent over the line. In the plug-cord connecting circuit I employsuitable relays for operating the supervisory or disconnect signals. Ihave preferably shown the talking battery to be a part of thesignaling-in battery, but it is to be understood that the talking sourceof electric current may be separate from the signaling source ofcurrent, if desired. I prevent the operator from listening-in on thelines during conversation between the subscribers, by adapting herlistening key to cut the sub scribers lines apart, when depressed.

I have also shown several modifications of my present invention, as willbe hereinafter described.

I will now more particularly describe my invention by reference to thedrawings, in which Figure 1 is a diagram showing two subscribers linesand the central station signaling and connecting apparatus; Fig. 2 showsthe line cutoff relay included in one side only, of the line; Fig. 3shows separate cut-off relays in the respective limbs of a metallicline, and groundedreturn ringing circuits for party-line ringing; andFig. 4 shows two individual supervisory relays connected to one side ofthe plug-cord talking circuit, and one supervisory relay for bothsupervisory signals connected to the other side of the said plug-cordcircuit.

Like characters refer to like parts in the several figures.

The line of subscriber A extends in two limbs K and I from a sub-stationto the central station where the said limbs pass through the respectivewindings Q and P of relay 1 and terminate in the respective connect-ionterminals U and V (or U and V,) of the several spring jacks 2 2 of amultiple switchboard. The thimble IV of one of the jacks 2 is normallyinsulated from the connection terminals U and V, and is used simply as aguide for the connecting plug. This jack is preferably used for theanswering jack. This insulated thimble W 110 is described and claimed inthe co-pending application of Parker and Corwin, Serial No. 571,846,filed July 13, 1910, on telephone system. Spring members 0 and L ofrelay 1 are permanently connected to the limbs K and I, respectively, ofthe line, and normally engage the respective contacts I and M. Contact Nis connected to one pole E preferably the positive, of battery 5,through conductor 0,, and contact M is connected to one pole 1),,preferably the negative, of

"battery at, through lamp 13,. Batteries 4 and 5 are connected inseries, and it is immaterial which is the positive or negative end poleof battery 4 5. hen armature T of relay 1 is attracted to the cores Sand R, sprin 's O and L are disengaged from con tacts N and M,respectively. In case of a grounded-return or common-return line, theground or common conductor constitutes one limb of the telephone line.

At the subscribers station I have shown one of a number of circuitarrangements in which the operation of the switch-hook G connects eitherthe receiver C and transmitter J, or the ringer E and condenser D, foruse over the line, depending on whether the switch-hook is raised orlowered. The operation of this instrument circuit is well understood andneed not be described here.

F or the line of subscriber B, I have shown modified forms of some ofthe apparatus used in connection with. line A. The other parts of line Bare similar to corresponding parts of line A and are denoted by likecharacters, respectively.

The line of subscriber B extends in two limbs K and I from thesub-station to the central station where the said limbs pass through therespective windings Q, and P, of the double-wound relay 3 and terminatein the respective connection terminals U and V or U and V,) of theseveral spring jacks 2 2 of the switchboard. Contacts N, and M, arepermanently connected to the limbs K and I, respectively, of the line,and normally engage the respective spring members O, and L2 of relay 3.Spring member 0, is connected to one pole E of battery 5, throughconductor 0,, and spring member L, is connected to pole D of battery 4t,through the winding of relay 6 and conductor 1),. Relay 6 controls thecircuit of battery 4 through lamp B as shown. When armature T, of relay3 is attracted to core 3,, springs 0, and L, are disengaged fromcontacts N, and M,, respectively.

In the plug-cord connecting circuit, the main conductors of theconnecting plugs 10 and 11 are connected together through the respectivecondensers I-L and I listen-.

ing key 12, and ringing key 13. Tip strand 0, of answering plug 10 isconnected to pole E of battery 5, through impedance coil M,.

Tip strand F, of calling plug 11 is normally connected topole E, "ofbattery 5,"through spring M,, contact spring L contact J conductor N andimpedance coil L,. Sleeve strand D, of answering plug 10 is connected tothe middle pole of batteryt 5, through winding K, of relay 7, andconductor Y,. Sleeve strand G, of calling plug 11 is normally connectedto the middle pole of battery t 5, through spring T contact Q conductorZ, winding X, of relay 8, and conductor Y,

Supervisory relays 7 and 8 are each provided with spring members F, andE, which are normally disengaged from each, other but adapted to bebrought into contact with each other. When core A, of relay 7 isenergized, armature R, is attracted thereto and thereby engages contactU, which closes ing I magnetizes the armature J, and produces a northpole N and a south pole S therein adjacent to one end Z, of core A, Itwill be noticed that whenever the current of battery 4 is closed throughwinding 1,, the north pole of armature J will always be at the same endthereof, and the south pole will always be at the other end thereof.When an energizing current traverseswinding K, of relay 7 in onedirection, a north pole will be produced in A, at Z, which will attractthe south pole of J and repel the north pole thereof. When, however, anenergizing current traverses winding K, in the opposite direction, asouth pole will be produced in A, at Z, which will attract the northpole of J, and repel the south pole thereof. This latter action "causesarmature J, to close the contact between spring F, and member E, whichcloses the circuit of battery 4: through conductors Y, and 11,,supervisory signal spring F,, contact 15,, and conductor G,, and causesWV, to display a signal. When the connecting plug 10 is inserted into aspring jack of a line, and the circuit of the line is open, the currentfrom battery i will traverse the winding K in one direction, throughconductor 'Y,, winding K,, sleeve strand 1),, ack spring V or V,,' lineconductor X, winding P of relay 1, spring L, contact M, lamp 3,, andconductor D and thereby cause core A, to operate. armature J, so as toclose the contact between spring F, and member E, If the circuit of theline is closed while such connection is made therewith, the current frombattery 5 will traverse the winding K, in the opposite direction,through impedance coil M,, tip strand C1,, jack spring U, line conductorY, winding Q of relay 1, line conductor K, substation A, line conductorI, winding P of relay 1, line conductor X, jack spring V or V,, sleevestrand 1),, winding K and conductor Y,, and thereby cause core A to acton armature J so as to break the contact F E or keep such contact fromclosing. In this manner the supervisory relay 7 operates and controlsthe supervisory signal W}. The operation of relay 8 is similar to thatjust described for relay 7, but the poles N and S are shown reversed.

The operators receiver Gr and one winding of repeating-coil D arebridged from contact K, to contact 55, of listening-key 12. Condenser Cthe other winding of repeating-coil D and the operators transmitter Fare connected in a loop as shown and to contact E The battery currentfor transmitter F is supplied from battery 5 through impedance coil 13,.Impedance coil A, is preferably connected to the receiver G, as shown,to provide means for making a busy-test. lVhen listening-key 12 isdepressed, springs L and R are disengaged from contacts J, and Prespectively, and engaged with contacts K and S respectively, and springE, is engaged with contact P Ringing generator 9, is adapted to give analternating, pulsating, intermittent, or interrupted current, asrequired, and is preferably bridged from contact N, to contact U,, ofringing key 18, as shown. When the ringing key 13 is depressed, springsand T are disengaged from contacts 0 and Q respectively, and engagedwith cont-acts N and U respectively.

The operation of the system is as follows: If subscriber A desires totalk with subscriber B, he lifts his telephone receiver C from theswitch-hook G and thereby closes the circuit of battery 4 5 throughconductor C contact N0 Spring 0, limb K of the telephone line,sub-station A, limb I of the telephone line, spring L, contact M, andlamp.

13 thus allowing current to flow through lamp B and light same, andthereby convey to the operator the signal for connection. The operatorthereupon lifts answering plug 10 and inserts same into a spring jack 2of line A, which closes the circuit of battery 5 through impedance coilM tip strand C jack spring U, winding Q; of cut-oil relay 1, limb K ofthe telephone line, sub-station A, limb I of the telephone line, windingP of relay 1, jack spring V,, sleeve strand 1),, winding K, ofsupervisory relay 7, and conductor Y thereby energizing relay 1 andcausing its armature r to be attracted, thus disengaging springs O andIJ from contacts N and M, respectively, and thereby disconnecting thecentral source of signaling current and the line signal lamp B, from thetalking telephone line. The circuit through lamp B is now broken atcontact M and consequently the line signal is extinguished. Supervisoryrelay '7 is now energized with current from battery 5, as abovedescribed,

and thereby keeps the contact F, E, open, thus preventing thesupervisory signaling device W from displaying a signal.

The operator then depresses her listening key 12 and thereby connectsher telephone set for use, in a manner well understood. In depressingthe listening key 12 the operator disengages springs L, and It, fromcontacts J and P respectively, and thereby cuts the central source ofcurrent from one talking conductor of the calling plug 11 and breaks thecontinuity of one of the talking strands, at contact P which stopsconversation from one subscribers line to another, when the connectingplugs are connected with the respective lines, While the listening key12 is depressed. It will thus be seen that it is impossible for theoperator to listen in on the lines while conversation is being carriedon therebetween, without breaking the talking circuit between the saidlines and thereby stopping conversation between the subscribers.

After learning that subscriber B is the subscriber called for, theoperator tests the line of subscriber B, to ascertain whether it is busyor not. In making the busy-test herein shown, the operator touches thetip E, of calling plug 11 to the ring IV of a multiple jack 2 of line B,while the listening key 12 is depressed, which closes a circuit frompole D of battery t through impedance coil A receiver G,, contact Kspring I contact spring M tip strand F ring N of a jack of line B,conductor X, winding 1 of relay 3, contact M spring L relay 6, andconductor 1),, back to pole I) of bat-- tery 4, if line B is not in use.Closing this circuit from pole D, of battery 4, through the receiver G,and back to the same pole D of battery 1, does not produce an impulsethrough the receiver G and line 13 therefore tests clear, or not busy.If line B is in use, the rings IV IV of the multiple jacks of line Bwill not be at the same potential as the tip I" or calling plug 11, andhence when the tip I is touched to a ring TV there will be a flow ofcurrent through the receiver G, and hence a click in the receiver whichindicates that the line is busy. Assuming that the operator finds theline of subscriber B to be not in use, she inserts the calling plug 11into aspring jack 2 of line B. She then depresses the ringing key 13 inthe usual manner, and at the same time restores the listening key 12 toits normal position. In depressing the ringing key 13, the operatorcloses the circuit of ringing generator 9 through contact N spring M tipstrand F jack spring U belonging to line B, winding (,1, of relay 3,limb IQ of the telephone line, switch-hook G, contact H, condenser D,ringer E, limb I of the telephone line, winding P, of relay 3, jack coirtact V, sleeve strand G spring T and contact U thus ringing the ringer Ewhich signals subscriber B, after which the ringing key 13 returns toits normal position.

Relay 3 (or relay 1) is constructed to respond to alternating,pulsating, intermittent, or interrupted currents, as well as to acontinuous, direct current. To render this relay thus responsive tothese different forms of currents, its armature (or armatures) is madeheavy and is pivoted so that it is withdrawn from the core (or cores) ofthe relay slowly by gravity. The withdrawal of the armature is thussluggish, and upon the passage of an alternating current through thewindings, or winding,vof the relay, a succeeding alternation willmagnetize the core (or cores) and thereby cause same to reattract thearmature, before said armature has had time to be withdrawn upon thecessation of magnetism due to the immediatelypreceding alternation. Theaction of pulsating, intermittent, or interrupted currents on thisrelay, is substantially the same as the action of an alternatingcurrent. Thus when relay 3 (or relay 1) is energized by a continuous,direct current, the armature (or armatures) thereof is held continuouslyto the core, (or cores) of the relay by a constant magnetic pull, andwhen it is energized by an alternating, pulsating, intermittent, orinterrupted current, the armature (or armatures) thereof is heldcontinuously to the core (or cores) .of the relay by an intermittentmagnetic pull, the pulsations of which are too rapid to permit thearmature to recede from the core, (or cores) appreciably, between thpulsations.

In sending a calling current over the line of subscriber B, the operatorenergizes relay 3 thereof by the said current, as above described, andthus causes its armature to i be attracted and thereby disengage springsand L from contacts N, and M respectively, thus disconnecting thecentral source of current 4- 5 and the line signaling apparatus (in thiscase relay 6) from the tele phone line during the sending of the saidcalling current. When the ringing lrey 13 is returned to its normalposition, relay 3 is de energized and springs 0 and L again engagecontacts N and M,, respectively. Before subscriber B lifts his telephonereceiver from the switch-hook, the circuit of the central source ofcurrent at is not closed over his telephone line, but the circuit ofbattery 4; is closed through conductor Y winding of supervisory relay 8,conductor 71, contact Q,,, spring T sleeve strand G jack spring V of oneof a number of multiple jacks of: line B, conductor X, winding P ofcut-oft relay 3, contact M spring L. the winding of relay 6, andconductor 1),. Eattery 4t does not, however allow sufficient current toflow through relays 3 and (8 to actuate their armatures, but it doesallow suflicient current to flow through supervisory relay 8 to actuatesame and thereby close 7 the contact between springs 13, and E ashereinbefore described, thus closing the circuit of battery 4 throughconductors Y, and X supervisory signal lamp Y spring F contact E andconductor G and lighting lamp Y lVhen subscriber B answers the call andlifts his telephone receiver C from the switch-hook G, the latter isdisengaged from contact H and engaged with contact F, thereby closingthe circuit of bat tery 5 through impedance'coil L conductor N contact Jspring L contact 0,, spring M tip strand F jack spring U, of a springjack 2 of line B, conductor Y, winding Q of relay 3, limb K of thetelephone line, switch-hook G, contact F, receiver G, transmitter J limbI of the telephone line, winding P of relay 3, conductor X, jack springV, sleeve strand G spring T contact Q conductor Z, winding X of relay 8,and conductor Y which energizes relay 3 and causes armature T thereol tobe attracted to core 8, and thereby disengage springs 0 and L fromcontacts N and M respec tively. The circuit through relay 6 is nowbroken at licl" and hence line-signal lamp B, is inoperative. Thecircuit of battery 5 now closed through winding X, of supervisory relay8, energizes this relay and actuates the armature H, thereof so as tobreak the contact between springs F and 15,, as hereinbefore described,thus opening the circuit through supervisory lamp Y and extinguishingits signal. Subscribers A and B are now connected for conversation witheach other, all of the signals being inactive.

\Vhen the conversation is completed and subscriber A hangs his telephonereceiver G upon the switch-hook G, the latter is disengaged from contactF and engaged with Contact H, thereby stopping the flow of or reducingthe current of battery 5 over the telephone line, in a manner wellunderstood,

preferably by placing condenser D in the" lamp B The current frombattery e now' flowing through relay 7 causes armature J thereof toclose the contact between springs F and 131,, as hereinbefore described,and thereby close the circuit of battery lthrough conductors Y and Xsupervisory lamp W conductor H springs F, and E and con ductor G andcause lamp W to light and thereby convey to the operator the signal fordisconnection.

The current now flowing through relay 1 is not sufficient to attractarmature T thereof, nor sufficient to cause lamp 1?), to light. It isobvious that if subscriber A should again take his receiver from theswitch-hook while connection is still made with his line, he would causehis supervisory lamp W to become extinguished. Thus by operating theswitch-hook the subscriber A may signal the operator for a secondconnection, through the agency of the supervisory signal. It will benoted that the current which closes the contact between springs F and Eof relay 7, traverses the winding K of this relay in a directionopposite to that in which the current which opens the said contact orprevents same from closing, traverses the same winding K .Vhensubscriber B hangs his telephone receiver 0 upon the switch-hook G, hebreaks the circuit of battery 5 over his telephone line, in a mannersimilar to that just described in connection with line A, and therebystops the flow of current through relay 3 and allows its armature tobecome released. lVhen armature T of relay 8 is released, it causesspring L to engage contact M and thereby close the circuit of battery tthrough conductor Y winding of supervisory relay 8, conductor Z, contactQ spring T sleeve strand G jack spring V of line B, conductor X, winding1?, of relay 8, contact M springL the winding of relay 6, and conductor1),. The current from battery a now flowing through relay 8 causesarmature H, thereof to close the contact between springs F and E as hereinbefore described, and thereby close the circuit of battery 4 throughconductors Y and X supervisory lamp Y conductor Z springs and E andconductor G and cause lamp Y, to light and thereby convey to theoperator the signal for disconnection. The current now flowing throughrelay 3 is not suflicient to attract armature '1, thereof, norsufficient to cause relay 6 to actuate its armature and thereby li htthe lamp B It is obvious that if subscriber B should again operate hisswitch-hook while connection is still made with his line, he wouldcorrespondingly operate his supervisory signal Y,,, the same asdescribed above in connection with subscriber A. When the operatorreceives bot-h disconnect signals from sulo scribers A and B,respectively, she with draws the connecting plugs 10 and 11 from theirrespective spring jacks, thus breaking the battery circuits through therelays 7 and 8, respectively, and thereby releasing their armatures, andat the same time restoring both telephone lines and all central stationcircuits and apparatus to their normal condition.

It is obvious that subscriber B may be the calling subscriber andsubscriber A the called subscriber, but it is not necessary to give adetailed description of the different operations performed in thusconnecting the system, as it would be practically the same as the abovedescription wherein subscriber A is the calling subscriber andsubscriber B is the called subscriber. In this case, plug 10 would beconnected with line B and plug 11 would be connected with line A, andthe order of operations with lines A and B would be reversed.

In Fig. 2 I have shown a single-wound cut-off relay 18 included in onelimb only of the talking telephone line. This relay 18 is adapted todisengage springs O and L from contacts N and M, respectively, when thearmatures thereof are attracted, and thus cut the line signal B, and thecentral station battery 14 from the talking telephone line.

In Fig. 3 I have shown a single-wound relay in each limb of thetelephone line. I have also shown telephone instruments connected to therespective limbs of the line, and have adapted the system for party-lineringing. When the connecting plug 11 is inserted into a spring jack 2,and connection is made bet-ween switch contacts P, and (2,, thedepression of ringing key 13, as described above, closes the circuit ofringing generator 9, through switch contacts P and Q contact N spring Mtip strand F jack spring U, winding Q of relay 19, limb K of thetelephone line, switch-hook G contact H condenser D ringer and ground NThis current from generator 9 rings the bell E and simultaneouslyenergizes relay 19 which causes its armature'to be attracted, asdescribed above in connection with dif ferent forms of energizingcurrents, and thereby disengage spring 0 from contact N thus clearinglimb K of the telephone line of all other circuit connections andthereby eliminating the possibility of sending a por tion of the ringingcurrent through the cen' tral battery or circuits other than the directline ringing circuit. When ringing key 13 is restored to its normalposition, relay 19 is dee'nergized and spring 0 therefore engagescontact N When the subscriber lifts his telephone receiver G, from theswitchhook G he causes switch-hook G to disengage contact H, and engagecontact F and thereby bridge the transmitter J and receiver C, acrossthe limbs K and l of the telephone line, for talking purposes. vl henthe line is connected for conversation, relays 19 and 20 are bothenergized, thereby causing their respective armatures to be attractedand thus disengage springs O and L from the respective conductors N andM. In ringing a subscriber, if contact P, of the generator switch isconnected with contact R the circuit of ringing generator 9 may beclosed through ringer E in a manner similar to that just described inconnection with ringer E in which case ringer E will operate and relay20 will simultaneously actuate its armature and thereby disengage springL from conductor M. Switch-hook Gr may be operated in a similar mannerto switch-hook G and thus connect its telephone receiver C andtransmitter J for con versation over the line, and also operate relays19 and 20 as above described.

In Fig. 4 I have dispensed with one condenser in the plug-cord circuitand have connected one supervisory relay 16 from this strand of theplug-cord circuit to the middle pole of battery t 5. Then I haveconnected supervisory relays 15 and 17 from the other strand of theplug-cord circuit, on respective sides of condenser H to one pole ofbattery 5. When either plug 10 or 11 is inserted into a spring jack ofan idle telephone line, the current from battery 4 will energize relay16 and thereby cause springs W and X, to engage contacts J and Krespectively, which closes the circuit of battery l through conductors Nand Q contact I spring V spring 7,, contact J supervisory lamp-1V andconductor 0 and also through conductor N contact L spring Y spring Xcontact K supervisory lamp Y and conductor 0 thus lighting the lamps Wand lVhen, however, plug 10 is connected with a telephone line and thecircuit of the line is closed, the circuit of battery 5 will be closedthrough relay 15 and the line, as well understood, and thereby causerelay 15 to actuate its armature and disengage spring V from contact Iwhich opens the circuit of lamp N and extinguishes its signal or keepsit from displaying a signal. If the circuit of the line is opened whilesuch con nection is made therewith, the circuit of battery 5 will beopened through relay15, and thereby allow spring V to again engagecontact I and by such engagement close the circuit of battery I throughlamp as described, which then displays its signal. Relay 17 controlssupervisory signal Y, in a manner similar to that just described inconnection with relay 15 and signal VV and hence need not be describedin detail. From this description it will be readily seen how supervisoryrelays 15, 16 and 17 operate and control the supervisory signals IV, andY Of course the cord circuit of Fig. l may be used in connection withthe line circuits of Figs. 1, 2 and 3, as desired. Other cord circuitsalso, may be used with these various line circuits.

While I have shown lamps for all central station signals, I desire it tobe understoon that other forms of signaling devices, such asannunciators having visual signals, or various other forms ofelectrically-operable signaling devices, may be used instead.

lthile I have illustrated this invention in connection with particulartypes of spring jacks, connecting plugs, keys; line cut-oft relays,supervisory relays, sources of electric current, and auxiliaryapparatus, I desire it to be understood that different types of theseseveral pieces of apparatus may be used. 1

I have shown and described this invention in connection with multipleswitchboard systems, but it is apparent that its features are alsoapplicable to systems of the single, transfer, or divided-board types.

I do not wish to limit this invention to all of the particular detailsherein set forth, as

various modifications thereof may be made or utilized without departingfrom the scope of the appended claims.

lVhat I claim as my invention is:

1. The combination with a telephone line and connection terminalstherefor, of a signal-controlling electromagnet normally connected withthe said line, a source of electricity also normally connected with thesaid line, a relay for disconnecting the said electromagnet and sourceof electricity from the said line, the said relay being included in thetalking limbs of the said line, a cord circuit terminating in aconnecting plug and adapted to be conductively connected to the line, asource of electricity associated with the said cord circuit and adaptedto be bridged across the metallic circuit of the line, and means forconductively connecting the last-mentionedsaid source with the saidincluded relay, when connection is made with the line, through a portionof the metallic talking circuit including the talking strands of thecord circuit, the main terminals of the connecting plug, the mainterminals of the line, and a portion of the talking limbs of thetelephone line, substantially as described,

2. The combination with a telephone line and connection terminalstherefor, of a sigrial-controlling electromagnet normally connected withthe said line, a relay for disconnecting the said electromagnet from theline and having windings included in the talking limbs of the line, acord circuit terminating in a connecting plug and adapted to beconcluctively connected to the line, a source of electricity associatedwith the said cord circuit and adapted to be bridged across the metalliccircuit of the line, and means for conductively connecting the saidsource with the windings of the said included relay, when connection ismade with the line, through a portion of the metallic talking circuitincluding the talking strands of the cord circuit, the main terminals-ofthe con necting plug,.the main terminals of the line, and a portion ofthe talking limbs of the telephone line, substantially as described.

3. The combination with a telephone line, of connection terminalsconnected to the line,

a signal-controlling electromagnet normally connected with said line, arelay for disconnecting said electromagnet from the line and included inboth talking limbs of the line, a cord circuit terminating in aconnecting plug and adapted to be placed in conductive relation with theline, a source of electricity associated with the said cord circuit andadapted to be connected to the line, and means for conductivelyconnecting the said source with the said included relay, when connectionis made with the line, through a portion of the talking circuitincluding the talking strands of the cord circuit, the main terminals ofthe connecting club, the main terminals of the line, and a portion ofthe talking limbs of the telephone line, substantially as described.

i. The combination with a telephone line, of connection terminalsconnected to said line, a signal-controlling electromagnet normallyconnected with the line, a relay for disconnecting said electromagnetfrom the line and having windings included in both talking limbs of theline, a cord circuit terminating in a connecting plug and adapted to beplaced in conductive relation with the line, a source of electricityconnected to the said cord circuit and adapted to be connected to theline, and means for conductively connecting the said source with thewindings of said included relay, when connection is made with the line,through a portion of the talking circuit including the talking strandsof the cord circuit, the main terminals of the connecting plug, the mainterminals of the line, and a portion of the talking limbs of thetelephone line, substantially as described.

55. The combination with a metallic telephone line, of connectionterminals at the central station connected to the line, a signal ingdevice normally connected to one limb of the telephone line, a signalingsource of electricity normally connected to the opposite limb of thetelephone line, a relay winding included in the talking circuit of thetelephone line and having a switch under its control adapted todisconnect the said signaling device from the said line, another relaywinding included in the talking circuit out the telephone line andhaving a switch under its control adapted to disconnect the saidsignaling source from the said line, a cord circuit terminating in aconnecting plug and adapted to be placed in conductive relation with thesaid line, a talking source of electricity associated with the cordcircuit and adapted to furnish the subscribefis station and saidincluded relay windings with energizing current when connection is madewith the line, and means for connecting the said talking source with thesubscribers station, through the talking circuit including the mainstrands of the cord circuit, the main terminals of the connecting plug,the line terminals, the said included relay windings and the limbs ofthe telephone line, substantially as described.

6. The combination with a telephone line having two limbs extending tothe central station, of connection terminals at the central stationconnected to the line, a signaling device normally connected to one limbof the line, a signaling source of electricity normally connected to theopposite limb of the line, a relay, the windings of which are includedin the respective limbs of the telephone line, the said included relaybeing adapted to remain in an operated condition during conversationover the line, thus disconnecting and to disconnect the signaling deviceand signaling source from the limbs of the telephone line duringconversation, a cord circuit terminating in a connecting plug andadapted to be placed in conductive relation with the line, a talkingsource of electricity associated with the cord circuit and adapted tofurnish the windings of said included relay with energizing current during conversation over said line, and means for connecting the saidtalking source with the subscribers station, when connection is madewith the line, through the metallic talking circuit including the mainstrands of the cord circuit, the main terminals of the connecting plug,the line terminals, the windings of said included relay, and the limbsof the telephone line, substantially as described.

'7. The combination with a metallic, calling telephone line andconnection terminals connected thereto, of a line signaling devicenormally connected to the said line, a source of electricity alsonormally connected to the said. line, a relay included in both 'alkinglimbs of the said line and provided with movable relay members whichnormally engage respective contacts but which are adapted to disengagethe said respective contacts when connection is made with the line andthe circuit of the line is closed, the said contacts being adapted todisconnect the said line signaling device and source of electricity fromthe said telephone line, a cord circuit terminating in a connecting plugand adapted to be conductively connected to the line, a central sour eof electricity associated with the cord circuit and adapted to furnishthe calling line with current when connection is made with the line inresponse to the call, and means for connecting the last-mentioned saidsource with the subscribers station, when connection is made with theline, through the talking strands of the cord circuit, the mainterminals of the connecting plug, the main line terminals, the saidincluded relay, and the talking limbs of the telephone line,substantially as described.

o &

lilti- 8. The combination with a calling tele phone line and connectionterminals con nected thereto, of a line signaling device normallyconnected to one limb of the said line, a signaling source ofelectricity normally connected to the other limb of the said line, relaywindings included in the respective talking limbs of the said line andhaving switches under their control adapted to disconnect the said linesignaling device and signaling source from the said line, a cord circuitterminating in a connecting plug and adapted to be conductivelyconnected to the line, a central source of electricity associated withthe cord circuit and adapted to furnish the line with current whenconnection is made therewith in response to the call, and means forconnecting the last-mentioned said source with the subscribers stationwhen connection is made with the line, through the talking circuitincluding the main strands of the cord circuit, the main terminals ofthe connecting plug, the main line terminals, the said included relaywindings, and the limbs of the telephone line, substantially asdescribed.

9. The combination with a calling telephone line and connectionterminals connected thereto, of a line signaling device normallyconnected to the said line, a signaling source of electricity alsonormally connected to the said line, a relay, the windings of which areincluded in the respective talking limbs of the telephone line, the saidrelay being provided with movable relay members which normally engagerespective contacts but which are adapted to disengage the saidrespective contacts when connection is made with the line and thecircuit of the line is closed, the saidrcontacts being adapted todisconnect the said line signaling device and signaling source from thesaid line, a cord circuit terminating in a connecting plug and adaptedto be conductively connected to the line, a central source ofelectricity associated with the cord circuit and adapted to furnish theline with talking current when connection is made therewith in responseto the call, and means for connecting the last-mentioned said sourcewith the subscribers station, when connection is made with the line,through the talking circuit including the main strands of the cordcircuit, the main terminals of the con necting plug, the main terminalsof the line, the windings of the said included relay, and the limbs ofthe telephone line, substantially as described.

10. The combination with a telephone line and connection terminalstherefor, of a signal-initiating device normally connected with saidline, a relay included in said line and adapted to disconnect the saiddevice from the line when in an operated condition,

a cord circuit terminating in a connecting plug and adapted to be placedin conductive relation with the line, a talking source of electricityassociated with the cord circuit, a disconnect source of electricityassociated with the cord circuit and with the said device, a supervisorydisconnect signal, an electromagnet through which the said sources areassociated with the cord circuit, said electromagnet being adapted tocontrol the supervisory disconnect signal, and means for closing thecircuit of said disconnect source through said electromagnet whenconnection is made with the line and the latter is not in use, saidelectromagnet-circuit including a talking strand of the cord circuit, amain terminal of the connecting plug, a line terminal, a port-ion of atalking limb of the telephone line, the said included relay, and thesaid signal-initiating device, sub stantially as described.

11. The combination with a telephone line and connection terminalstherefor, of a signal-initiating device normally connected with saidline, a relay the windings of which are included in the respectivetalking limbs of the line, said relay being adapted to disconnect thesaid device from the line when in an operated condition, a cord circuitterminating in a connecting plug ancl adapted to be conductivelyconnected to the line, a talkig source of electricity associated withthe cord circuit, a disconnect source of electricity associated with thecord circuit and with the said device, a supervisory disconnectsignal,an electromagnet through which the said sources are associated with thecord circuit. said electromagnet bein adapted to control the supervisorydisconnect signal, and means for closing the circuit of said disconnectsource through said electromagnet when connect-ion is made with the lineand the latter is not in use, said electromagnetcircuitincluding atalking strand of the cord circuit, a main terminal of the connectingplug, a line terminal, a portion of a talking limb of the telephoneline, a winding of said included relay, and the said signal-initiatingdevice, substantially as described.

12. The combination with a telephone line and connection terminalstherefor, of a signalinitiating device normally connected with the saidline, a source of electricity normally connected with said line, relaywindings included in the respective talking limbs of the telephone lineand having switches under their control adapted to disconnect the saiddevice and source from the line, a cord circuit terminating in aconnecting plug and adapted to be placed in conductive relation with theline, a source of electricity associated with the cord circuit and withthe said device, a supervisory disconnect signal, an electromagnetthrough which the lastmentioned said source is associated with the cordcircuit, the said electromagnet being adapted to control thesupervisory-discos nect-signal when connection is made with the line,and means for closing the circuit of the last-mentioned said sourcethrough the said electro-magnet when connection is made with the line,the said electromagnet-circuit including a talking strand of the cordcircuit, a main terminal of the connecting plug, a line terminal, aportion of a talking limb of the line, an included relay winding, andthe said signal-initiating device, substantially as described.

13. The combination with a telephone line, of a connection terminalconnected thereto, a signaling device and source of electricity normallyconnected to the line, a relay included in both limbs of the talkingcircuit of the line and adapted to disconnect the said device and sourcefrom the line when in an operated condition, a cord circuit, a centralsource of electricity associated with the cord circuit and adapted tofurnish the line with current for talking purposes when connection ismade therewith, means for operating the said relay from thelast-mentioned said source during conversation over the line, and meansfor sending a calling cur rent over either limb of the line in calling asubscriber and thereby operating the said relay and thus clearing thesaid line of the said signaling device and first-mentioned said source,substantially as described.

14:. The combination With a telephone line, of a connection terminalconnected thereto, a line signaling device normally connected to thesaid line, a relay included in both talking limbs of the line andadapted to disconnect the said device from the said line when inanoperated condition, closing the circuit of the said line at thetelephone thereof being in no way adapted to operate the said includedrelay when no connection is made with the said line, a cord circuitterminating in a connecting plug and adapted to be electricallyconnected to the said line, a calling source of electricity, a ringingkey for connecting the said calling source with the line, and means forsending a calling current over the line, when connection is made withthe line of a called subscriber, and at the same time actuating the saidincluded relay by this said calling current thus sent over the talk ingcircuit including a strand of the cord circuit, a main terminal of theconnecting plug, a line terminal, the said included relay, and a limb ofthe telephone line to the telephone thereof, with a suitable return, andthereby disconnecting the said line signaling-device from the said line,substantially as described.

15. The combination with a telephone line and connection terminalsconnected thereto, of .a line signaling-device and source of electricitynormally connected to the said line,

a relay included in both talking limbs of the telephone line and adaptedto respond to continuous and to non-continuous currents and disconnectthe said signaling-device and source from the line when in an energizedcondition, a connecting cord terminating in a connecting plug andadapted to be conductively connected to the line, a talking source ofelectricity normally connected to the said cord, a calling source ofelectricity adapted to be bridged across the talking strands of the cordcircuit, a ringing key adapted to connect the said calling source withthe line of a called subscriber and to disconnect the said talkingsource therefrom, when connection is made with the line, the saidcalling source being adapted to energize the said included relay when acurrent therefrom is sent over the line, substantially as described.

16. The combination with a telephone line, of a relay included in thetalking limbs of the line, a signaling device connected with the line, atelephone connected with the line, a source of calling current, andmeans for sending electricity from the said source through either limbof the line and thereby giving a signal at the telephone andsimultaneously causing the said relay to disconnect the said signalingdevice from the line.

17 The combination with a telephone line, of a relay included in bothtalking limbs of the line, a source of electricity and anelectroresponsive device connected with the line, a telephone connectedwith the line, a source of calling current, and means for closing thecircuit of the said calling source through the said relay, a limb of theline, and the telephone, and thereby producing a signal at the telephoneand simultaneously causing the said relay to disconnect the firstmentioned said source and said electroresponsive device from the line.

18. The combination with a telephone line and connection terminalstherefor, of a signaling device normally connected to one limb of thetelephone line, a signaling source of electricity normally connected tothe other limb of the telephone line, a relay included in the talkinglimbs of the telephone line and adapted to respond to continuous and tonon-continuous currents, to disconnect the said signaling device andsignaling source from the limbs of the telephone line when in anoperated condition, a cord cir cuit terminating in a connecting plug andadapted to be conductively connected to the line, a talking source ofelectricity normally associated with the said cord circuit, a callingsource of electricity normally disconnected from the said cord circuitand adapted to transmit a non-continuous current, and a ringing keyadapted to connect the said calling source to the limbs of the line ofthe called subscriber and to disconnect the said talking sourcetherefrom, the said calling source being adapted to actuate the saidincluded relay whether sent over either one, or both, of the limbs ofthe telephone line, with a suitable return, substantially as described.

19. The combination with a metallic telephone line and connectionterminals connected thereto, of a signaling device and source ofelectricity normally connected to the said line, a relay th windings ofwhich are included in the respective talking limbs of the metallic line,the said relay being adapted to respond to both continuous andnon-continuous currents and to disconnect the said signaling device andsource from the said line when in an operated condition, a cord circuitterminating in a connecting plug and adapted to be placed in conductiverelation with the said line, a talking source of electricity normallyassociated with the cord circuit and adapted to furnish the subscribersstation with current for talking purposes when the line is in use, acalling source of electricity normally disconnected from the said cordcircuit and adapted to give a non-continuous current to operate the saidincluded relay when a current therefrom is sent over the line of thecalled subscriber, a ringing key for disconnecting the said talkingsource from the limbs of the said line and connecting the said callingsource thereto, and means for closing the circuit of the calling sourcethrough the called subscribers station over a circuit including thetalking strands of the cord circuit, the main terminals of theconnecting plug, the main line terminals, the windings of the saidincluded relay, and the talking limbs of the telephone line,substantially as described.

20. The combination wit-h a metallic tele phone line and a relayincluded in the talking circuit thereof, of talking contacts of a springjack connected to the respective limbs of the said line, a signalingdevice normally connected to the said line but arranged to bedisconnected therefrom by the said included relay when the latter is inan operated condition, a central source of electricity adapted to beeonductively connected with the line and to furnish the sub-stationtransmitters with current for talking purposes when the line is in use,a plug provided with connection terminals and adapted to be connectedwith the said spring jack, a cord circuit associated with the said plugand normally connected with the said central source of electricity, asecond central source of electricity associated with the said signalingdevice and cord circuit, and also used for testing purposes, the saidsources being both used to operate the said signaling device, and anoperators listening-in key adapted to cooperate with the said cordcircuit in its operations, substantially as described.

21. The combination with a telephone line mally connected to the saidline butadapted to be disconnected therefrom by at least one of the saidincluded relay windings, a plu- 4 rality of talking contacts formingconnection terminals for the said line, a cord circuit terminating in aconnectingplug and adapted to be connected to the said line, a centralsource of electricity associated with the cord circuit and adapted tofurnish talking current to the sub-station transmitters of the line whenthe said line'is in use, a central source of testing current associatedwith the said cord circuit and with the said signaling device, both ofthe said, sources being used to give the line signal, an operator stelephone set, akey adapted to connect the operators telephone-set withthe said cord circuit, a testing plug provided with a test contactadapted to be placed in con-Q ductive relation with the operatorstelephone, and means for changing the potential of the said plurality oftalking contacts of the line for testing purposes, when connec tion ismade with the line, substantially as described.

22. The combination with a metallic telephone line and windings of arelay included in the talking circuit thereof, of a line signal normallyassociated with the said line, means for controlling the said linesignal by the said included relay, a plurality of talking contactsforming connection terminals for the said line, the said terminals beingarranged at the several sections of a switchboard, a plug-cord circuit,a central source of talking current associated with the plug cordcircuit and normally with the said line, a source oftesting currentassociated with the plug-cord circuit and used for operating the saidline signal, an operators telephone set, a key adapted to connect'theoperators telephone-set with the said plug-cord circuit, and means forutilizing the said plugcord circuit in connection with the said talkingcontacts at the switchboard, substansaid line and supplied withelectricity from electrical sources at the central station, asignal-controlling electromagnet normally connected to the said line butadapted to be disconnected therefrom by current in at least one of thesaid included relay windings,supervisory-signal-controlling-electromagnets and a supervisory signalunder control thereof, a plug-cord circuit with which the saidsupervisory-electromagnets are associated, the said plug-cord circuitbeing adapted to be connected to the limbs of the said line at the saidspring jacks, a central source of current associated with the plugcordcircuit and normally with the line, but adapted to be disconnected fromthe said line by current in at least one of the said included relaywindings, means for testing the condition of the line at any of the saidspring acks, means for operating one of the saidsupervisory-signal-controlling electromagnets over a circuit including aportion of a. talking limb of the line, and means for placing at leastone of the said supervisorysignal-cont-rolling-electromagnets under thecontrol of the subscriber when connection is made with the telephoneline, all cooperating for the purposes of signaling and talking,substantially as described.

2%. The combination with a metallic telephone line, of a relay thewindings of which are included in the respective talking limbs of thesaid line, a line signaling device and source of electricity normallyconnected with the respective talking limbs of the line but adapted tobe disconnected therefrom by the operation of the said included relay, aspring jack having aterminal for each of the limbs of the said line andconnected thereto, a cord circuit normally terminating in two connectingplugs and adapted to be connected to respective spring jacks ofsubscribers telephone lines, a ringing key through which the limbs ofthe cord circuit normally extend, a listening-in key through which thelimbs of the cord circuit normally extend, and which is adapted forbridging an operators telephone-set across the talking limbs of the cordcircuit and in so doing breaking the continuity of one of the talkinglimbs of the cord circuit be tween the said connecting plugs and therebyrendering conversation between the subscribers which are connected tothe said cord circuit, impossible, a source of eleotricity associatedwith the cord circuit, a calling source of current associated with theringing key, and means for connecting subscribers for conversationthrough the said cord circuit when the said connecting plugs areconnected to the said subscribers lines, substantially as described.

25. The combination in a metallic telephone system, of two subscriberslines extendin to the central station terminatin I n b l u I u insuitable respective spring acks and including a winding of a relay ineach of the to be connected to the spring jacks, a central source ofcurrent associated with the cord circuit and adapted to be used forsignaling and talking purposes, and means for connecting the saidsubscriber for conversation with each other through the cord circuit,substantially as described.

26. The combination with a metallic telephone line adapted to beincluded in a talking circuit, of relay winding included in therespective limbs of said talking circuit and adapted to actuate theirarmature when conducting a continuous or noncontinuous current over alimb of the metallic line, connection terminal for the respective limbsof said line, a cord circuit mrminating in a connecting plug and adaptedto be connected with said line, a source of calling current, a ringingkey adapted to connect said calling source with said cord circuit, andmeans for connecting said calling source with the subscribers station,when connection is made with the line, whereby at least one of the saidincluded relay windings operates the said armature and thereby clearsboth sides of said line of all. apparatus and auxiliary circuits notincluded in the metallic talking circuit, from said connection terminalsto said subscriber station, thus enabling said calling current to besent out direct over either side of the line, with a suitable return,for party-line ringing, substantially as described.

27. The combination with a metallic telephone line adapted to beincluded in a talking circuit, of a line signal, a cut-oil relay thewindings of which are included in the respective limbs of said line, acord circuit, a ource of electricity, a supervisory signalcontrollingelectromagnet through which the said source is associated with the cordcircuit, and means for closing the circuit otthe said source through thesaid electromagnet and the said included windings, when the line is inuse, over a portion of the main strand of the cord circuit and thetalking limbs of the telephone line, substantially as described.

28. The combination with a telephone line having a limb extending to acentral station, of a relay included in the said limb, a signalingdevice normally connected to the said limb but adapted to bedisconnected therefrom by the said included relay, a plug cord circuitadapted to be conductively connected to the said line, a supervisorysignal, supervisory relays associated with the said cord circuit, adivided source of electricity associated with the said cord circuitthrough the said supervisory relays, means for operating one of the saidsupervisory relays over a circuit including a portion of the path oftalking currents, and means for causing the subscriber to contr l theoperation of the said included relay, by opening and closing a switch athis telephone station, when connection is made with the line, and alsoto control the operation of at least one of the said supervisory relaysduring such connection, by opening and closing the said switch, tooperate the supervisory signal at the central station, substantially asdescribed.

29. The combination in a telephone system, of a line extending from asubscribers station to a central station, a relay the windings of whichare included in the respective talking limbs of the line, the said relaybeing used as a line cut-oft relay, line signaling apparatus normallyconnected to the said line when the latter is not in use, but adapted tobe disconnected therefrom by the said included relay when the line is inuse, a subscribers sub-station associated with the said line andincluding a transmitter, receiver, bells, condenser and switchhook, lineterminals at the central station, in the form of spring jacks, connectedto the respective limbs of the said line, a cord circuit terminating inconnecting plugs and adapted to be placed in conductive relation withthe said line, supervisory signal-eontrolling electromagnets normallyassociated with the said connecting plugs, supervisory signals, anoperators listeningin key, a ringing key, a calling source ofelectricity, and a divided source of electricity associated with thecord circuit and normally with the said line, a portion. of said dividedsource being adapted to furnish current for sub-station transmitters,another portion of said divided source being adapted to operate thesupervisory signals, and both portions of said divided source being usedfor operating the line signaling apparatus and the supervisory signalingapparatus, the supervisory signal-controlling electromagnets beingoperated over circuits including portions of the talking conductors, allfor the purpose of connecting subscribers stations together and therebyfacilitating conversation between the said subscribers, and fordisconnecting the said lines and said stations when same are not in use,substantially as described.

30. The combination with a telephone line extending from a substation toa central station, of a relay at the central station included in bothlimbs of the talking telephone line, said relay being operated onlywhile connec tion is made with the line,a signaling circuit normallyconnected to the line but adapted to be disconnected therefrom by thesaid relay when the latter is in an operated condi tion, talkingapparatus and signaling apparatus connected with the telephone line atthe substation, a switch-hook at the sub-station, means for sending acalling currentthrough the said relay, the telephone line and the saidsub-station signaling apparatus, thereby operating the said relay andsignaling the subscriber, and means for sending a second current throughthe said relay, the telephone line and the said substation talkingapparatus, thereby operating the said relay and supplying thesubscribers transmitter with current for talking purposes, substantiallyas described.

31. The combination with a metallic electrical transmitting lineextending conductively to a connection terminal or terminals and havingone or more branch connections from the main transmission limb or limbsof the line, of electroresponsive mechanism having energizing meanstherefor included in both main transmission limbs of the line wherebycurrent in either one or both of the main limbs of the line causes theoperation of the said electroresponsive mechanism, the lattercontrolling the said branch connection or connections from the line,with respect to the main line. I

32. The combination with a metallic telephone line extendingconductively to a connection terminal or terminals and having one ormore branch connections from the talking limb or limbs of the line, ofrelay mechanism having energizing means therefor included in bothtalking limbs of the line whereby currentin either one or both of thetalking limbs of the line causes the operation of the said relaymechanism, the latter controlling the said branch connection 01'connections from the line, with respect to the main line.

33. The combination with a metallic electrical transmitting lineextending conductively to a connection terminal or terminals, ofelectroresponsive mechanism having energizing means therefor included inboth main transmission limbs of the line whereby current in either oneor both of the main limbs of the line causes the operation of the saidelectroresponsive mechanism, and suitable apparatus under control of thesaid electroresponsive mechanism.

3%. The combination with a metallic telephone line extendingconductively to a con nection terminal or terminals, of relay mechanismhaving energizing means therefor included in both talking limbs of theline whe eby current in either one or both of the talking limbs of theline causes the operation of the said relay mechanism, and suitableapparatus under control of the said relay mechanism.

35. The combination with a telephone line, of electrcresponsivemechanism having low-resistance energizing means therefor in the path oftalking currents, and suitable apparatus under control of the saidelectroresponsive mechanism.

36. The combination with a metallic telephone line, of electroresponsivemechanism having low resistance energizing means therefor in both limbsof the line in the path of talking currents, and suitable apparatusunder control of the said electroresponsive mechanism.

37. The combination with an electrical transmitting line,ofelectroresponsive mechanism having energizing means therefor includedin a main transmission limb of the line, the said mechanism beingadapted to be held continuously in an operated condition by either acontinuous or a non-continuone current, and suitable apparatus undercontrol of the said electroresponsive mechanism.

38. The combination with a telephone line, of relay mechanism havingenergizing means therefor included in a talking limb of the line, thesaid mechanism being adapted to be held continuously in an operatedcondition by either a continuous or a noncontinuous current, andsuitable apparatus under control of the said relay mechanism.

39. The combination with a metallic electrical transmitting line, ofelect-roresponsive mechanism having energizing means therefor includedin both main transmission limbs of the line, the said mechanism beingadapted to be held continuously in an operated condition by either acontinuous or a non-continuous current, and suitable apparatus undercontrol of the said electroresponsive mechanism.

to. The combination with a metallic telephone line, of relay mechanismhaving ener gizing means therefor included in both talking limbs of theline, the said mechanism being adapted to be held continuously in anoperated condition by either a continuous or a non-continuous current ineither one or both of the talking limbs of the line, and suitableapparatus under control of the said relay mechanism.

41. The combination with an electrical transmitting line having one ormore branch connections from the main transmission limb or limbs of theline, of electroresponsive mechanism having energizing means thereforincluded in a main transmission limb of the line and adapted to beoperated by a calling current sent out over the line whereby the saidbranch connection or connections are disconnected from the line duringthe sending of the said calling current.

42. The combination with a telephone line having one or more branchconnections from the talking limb or limbs of the line, of relaymechanism having energizing means therefor included in a talking limb ofthe line and adapted to be operated by a calling current sent out overthe line whereby the said branch connection or connections aredisconnected from the line during the sending of the said callingcurrent.

43. The combination with a metallic electrical transmitting line havingone or more branch connections from the main transmission limb or limbsof the line, of electroresponsive mechanism having energizing meanstherefor included in both main transmission limbs of the line andadapted to be operated by a calling current sent out over either one orboth of the main limbs of the line whereby the said branch connection orconnections are disconnected from the line during the sending of thesaid calling current.

4%. The combination with a metallic telephone line having one or morebranch connections from the talking limb or limbs of the line, of relaymechanism having energizing means therefor included in both talkinglimbs of the line and adapted to be operated by a calling current sentout over either one or both of the talking limbs of the line whereby thesaid branch connectlon or connections are disconnected from the lineduring the sending of the said callmg current.

45. The combination with a metallic electrical transmitting line havingone or more branch connections from the main transmission limb or limbsof the line, of electroresponsive mechanism having energizing meanstherefor included in both main transmission limbs of the line andadapted to control the said branch connection or con nections from theline, the said electroresponsive mechanism being adapted to be operatedby calling current sent out over the line whereby the said callingcurrent in either limb of the line causes the electro responsivemechanism to simultaneously clear the line of one or more of the saidbranch connections. a

4:6. The combination with a metallic telephone line having one or morebranch connections from the talking limb or limbs of the line, of relaymechanism having energizing means therefor included in both talkinglimbs of the line and adapted to control the said branch connection orconnections from the line, the said relay mechanism being adapted to beoperated by calling current sent out over the line whereby the saidcalling current in either limb of the line causes the relay mechanism tosimultaneously clear the line of one or more of said branch connections.

47. A telephone line having an electroresponsiv device associatedtherewith, a supervisory signal-initiating device under control of thesaid electroresponsive device when connection is made with the line, andmeans for sending calling current out over the line for signalingpurposes and to actuate the said electroresponsive device.

48. A metallic telephone line having electroresponsive mechanismassociated with the limbs thereof, supervisory signaling mechanism undercontrol of the said electrore sponsive mechanism when connection is madewith the line, and means for sending calling current out over eitherlimb of the line for signaling purposes, the said current in either limbof the line simultaneously actuating the said electroresponsivemechanism.

49. The combination with an electrical transmitting line, ofelectroresponsive mech anism having energizing means therefor includedin a main transmission limb of the line, the said mechanism beingadapted to be held continuously in an operated condition by either acontinuous or a non-continuous current, a connecting circuit for theline, and a signal-initiating device associated with the said connectingcircuit and adapted to be placed under control of the saidelectroresponsive mechanism when connection is made with the line.

means therefor included in a talking limb of the line, the saidmechanism being adapt ed, to be held continuously in an operatedcondition by ither a continuous or a noncontinuous current, a connectingcircuit for the line, and a signal-initiating device associated with thesaid connecting circuit and adapted to be placed under control of thesaid relay mechanism when connection is made with the line.

51. The combination with a metallic electrical transmitting line, ofelectroresponsive mechanism having energizing means therefor included inboth main transmission limbs of the line, portions of the said mechanismbeing adapted to be held continu-- ously in an operated condition byeither a continuous or a non-continuous current in either one or both ofthe limbs of the line, a connecting circuit for the line, and asignal-initiating device associated with the said connecting circuit andadapted to be placed under control of the said electroresponsivemechanism when connection is made with the line.

52. The combination with a metallic telephone line, of relay mechanismhaving on ergizing means therefor included in both talking limbs of theline, portions of the said mechanism being adapted to be heldcontinuously in an operated condition by either a continuous or anon-continuous current in either one or both of the limbs of the line, aconnecting circuit for the line, and a signal-initiating deviceassociated with the said connecting circuitand adapted to be placedunder control of the said relay mechanism when connection is made withthe line.

53. The combination with an electrical transmitting line having one ormore branch connections from the main transmission limb or limbs of theline, of electroresponsive mechanism having energizing means thereforincluded in a main transmission limb of the line and adapted to beoperated by a calling current sent out over the line whereby the saidbranch connections are disconnected from the line during the sending ofthe said calling current, aconnecting circuit for the line, and asignal-initiating device associated with the said connecting circuit andadapted to be placed under control of the said electroresponsivemechanism when connection is made with the line.

54-. The combination with a telephone line having one or more branchconnections from the talking limb or limbs of the line, of relaymechanism having energizing means thereforincluded in a talking limb ofthe line and adapted to be operated by a calling current sent out overthe line whereby the said branch connections are disconnected from theline during the sending of the said calling current, a connectingcircuit for the line, and a signal-initiating device associated with thesaid connecting circuit and adapted to be placed under control of thesaid relay mechanism when connection is made with the line.

55. The combination with a metallic electrical transmitting line havingone or more branch connections from the main transmission limb or limbsof the line, of electroresponsive mechanism having energizing meanstherefor included in both main transmission limbs of the line andadapted to be operated by a calling current sent out over either one orboth of the main limbs of the line whereby the said branch connectionsare disconnected from the line during the sending of the said callingcurrent, a con necting circuit for the line, and a signalinitiatingdevice associated with the said connecting circuit and adapted to beplaced under control of the said electroresponsive mechanism whenconnection is'made with nal-initiating device associated with the said,

connecting circuit and adapted to be placed under control of the saidrelay mechanism when connection is made with the line.

57 The combination with a metallicelectrical. transmitting line havingone or more branch connections from the main transmission limb or limbsof the line, of electroresponsive mechanism having energizing meanstherefor included in both main transmission limbs of the line andadapted to control the said branch connection or connections from theline, the said electroresponsive mechanism being adapted to be operatedby calling current sent out over the line whereby the said callingcurrent in either limb of the line causes the electroresponsivemechanism to simultaneously clear the line of one or more of the saidbranch connections therefrom, a connecting circuit for the line, and asignal-initiating device associated with the said connecting circuit andadapted to be placed under control of the said electroresponsivemechanism when connection is made with the line.

58. The combination with a metallic tele phone line having one or morebranch connections from the talking limb or limbs of the line, of relaymechanism having energizing means therefor included in both talkinglimbs of the line and adapted to control the said branch connection orconnections from the line, the said relay mechanism being adapted to beoperated by calling cur rent sent out over the line whereby the saidcalling current in either limb 01''- the line causes the relay mechanismto simultaneously clear the line of one or more of the said branchconnections therefrom, a connecting circuit for the line, and asignalinitiating device associated with the said connecting circuit andadapted to be placed under control of the said relay mechanism whenconnection is made with the line.

59. A telephone line circuit for signaling a central station, a relayassociated with the line, a normally-open branch circuit from the saidline circuit containing a winding of the said relay, a line signal undercontrol of the said relay, and means for closing the said normally-openbranch circuit when con nection is made with the line whereby the saidrelay Winding is then placed in the talking circuit.

60. A telephone line circuit for signaling a central station, a relayassociated with the line, a normally-open branch circuit from the saidline circuit containing a winding of the said relay, a line signal undercontrol of the said relay, and means for closing the said normally-openbranch circuit through a connection terminal when connection is madewith the line, to atlect the condition of the said relay and place thesaid rela winding in the talking circuit.

61. A telephone line extending from a substation to central station, aconnecting circuit for the line, a normally non-polarized supervisoryrelay associated with the connecting circuit exterior of the talkingcircuit and constructed so that one operation thereof is caused bycurrent therethrough in one direction, and another operation thereof iscaused by current therethrough in the opposit-e direction, suitableelectrical supply, a slgnahng device under control of the said relay,and means for supplying current to i the said relay over a portion ofthe line in opposite directions to cause the relay to operate andcontrol the said signaling device.

62. An electrical transmitting line extend ing from a substation to acentral station, a connecting circuit for the line, a normallynon-polarized electrically-operable device associated with theconnecting circuit oxterior of the main circuit and constructed so thatcurrent sent therethrough in opposite directions causes diil'erentoperations there of, an electroresponsive device under control of thesaid electrically-operable device, and means for supplying current tothe said electrically-operable device over a portion of the line inopposite directions, to control the said electroresponsive device.

(53. The combination with a telephone line and a connecting circuittherefor, of a normally non-polarized supervisory relay associated withthe connecting circuit exterior of the talking circuit and constructedso that different opemtions thereof are caused by opposite energizationsthereof, a signaling device under control of the said relay, and meansfor supplying current to the said relay over a portion of the line inopposite directions to cause the relay to operate and control the saidsignaling device.

64-. The combination with an electrical transmitting line and aconnecting circuit therefor, oil a, normally non-polarizedelectrically-operable device associated with the connecting circuitexterior of the main circuit and constructed so that diilerentoperations thereof are caused by opposite energizations thereof, anelectroresponsive device under control of the said electricallyoperabledevice, and means for supplying current to the saidelectrically-operable device in opposite directions, to control the saidelectroresponsive device.

35. In a telephone system, the combina tion with a telephone line havinga line signal, of acord circuit for establishing connection with theline for conversation, a cut-off device associated with the line andadapted when operated to render the line signal inoperative, asupervisory relay associated with the cord circuit, a suitable signaladapted to be controlled by the supervisory relay, and means forestablishing a path for current through the supervisory relay and thesaid cut-01f device when connection is made with the line, the currentin the said path being in one direction when the subscribers telephoneis on its hook, whereby the supervisory relay is caused to display itssignal, and in the opposite direction when 66. A telephone line circuitfor signaling a central station, a relay associated with the line,anor1nallyopen branch circuit from the said line circuit containing awinding of the said relay, a signaling device under control of the saidrelay, and means for closing the said normally-open branch circuit whenconnection is made with the line whereby the said relay winding is thenplaced in the talking circuit.

67. A telephone line circuit for signaling a central station, a relayassociated with the line, a normally-open branch circuit from the saidline circuit containing a winding of the said relay, a signaling deviceunder control of the said relay, and means for closing the saidnormally-open branch circuit through a connection terminal whenconnection is made with the line, to affect the condition of the saidrelay and place the said relay winding in the talking circuit.

(58. A. telephone line having an electroresponsive device normallyassociated therewith at a central station, and means for sending callingcurrent out over the line for signaling purposes, the said callingcurrent simultaneously actuating the said electroresponsive device.

69. A metallic telephone line having electroresponsive mechanismnormally associated with the limbs thereof at a central statron, andmeans for sending calling current out over the limbs of the llIIGfOIsignaling purposes, the said calling current in either limb of the linesimultaneously actuating the said electroresponslve mechanism.

70. The combination with a telephone line, of relay mechanism havinglow-resist- As inventor of the foregoing I hereunto subscribe my nameinthe presence of two subscribing witnesses, this 16th day of June, A. D.1904. r 7

FREDERICK R. PARKER. Witnesses: I

R. G. PARKER, WM. F. VioLn'rr.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner Washington, D. U.

of Patents,

